To explore the mechanism by which enhancers maintain gene expression, we have assessed the ability of an enhancer and derivative mutants to influence silencing and nuclear location of a transgene.… (More)

A casual examination of the globin literature would leave most readers with the impression that all aspects of beta-globin gene regulation are controlled by the upstream locus control region (LCR).… (More)

Transcriptional interference is the influence, generally suppressive, of one active transcriptional unit on another unit linked in cis. Its wide occurrence in experimental systems suggests that it… (More)

Transcriptional enhancers are traditionally considered to regulate the rate at which a linked promoter transcribes mRNA, but recent experiments suggest a reevaluation of this model is necessary.… (More)

A constitutive DNase I-hypersensitive site 5' of the chicken beta-globin locus, termed 5'HS4 or cHS4, has been shown to insulate a promoter from the effect of an upstream enhancer and to reduce… (More)

Enhancer elements have been shown to affect the probability of a gene establishing an active transcriptional state and suppress the silencing of reporter genes in cell lines, but their effect in… (More)

Expression of transgenes in mice, when examined with assays that can distinguish individual cells, is often found to be heterocellular, or variegated. Line-to-line variations in expression of a… (More)